The present invention relates generally to the examination of skin, mucosa and cervical tissues for the purpose of detecting cancer and precancerous conditions and relates more particularly to a novel apparatus for use in performing examinations of the aforementioned types.
Cutaneous melanoma is a disease of increasing clinical and economic importance, both in the United States and abroad. For this reason, the early detection of cancerous and precancerous lesions is particularly important at preventing the progression of the disease. To highlight the importance of early detection, data from the National Cancer Database of the United States indicate that 37% of those patients who have been diagnosed with melanoma have advanced primary lesions that can spread to regional lymph nodes or beyondxe2x80x94often with dire consequences.
Despite the fact that approximately 1 in 87 Americans will be diagnosed with melanoma during his/her lifetime, the public, on balance, lacks the foresight and the ability to perform satisfactory self-examinations. In addition, the examination of skin by primary care, non-dermatologist physicians is uncommon, and such non-dermatologist physicians are poorly prepared to recognize and to diagnose melanomas. Notwithstanding the above, the benefits associated with skin examinations are becoming increasingly more apparently as an increase in skin examinations has been correlated with a reduction in the incidence of melanoma, as well as with a reduction in the development of advanced disease among melanoma patients.
Skin examinations typically involve visually inspecting the skin for lesions and evaluating any detected lesions according to well-defined criteria, such as the ABCD rule wherein A=asymmetry, B=border irregularity, C=color variability and D=diameter  greater than 6 mm. Potential melanomas detected according to the foregoing technique are then typically biopsied in order to permit a final diagnosis.
The visual inspection of skin is typically performed with the unaided eye, with a hand-held magnifying glass or with the assistance of an instrument known as a dermatoscope. One problem associated with visually inspecting skin with the unaided eye or with a magnifyring glass is that much of the light used to illuminate the skin being examined is difflusely reflected by the outermost surface of the skin, thereby obfuiscating much of the subsurface structures of interest. Another problem associated with visually inspecting skin with the unaided eye or with a magnifying glass is that certain lesions are too small to be readily detected.
A dermatoscope is typically a hand-held device that is constructed to address both of the shortcomings identified above. A dermatoscope typically comprises an elongated, hollow housing having a pair of open ends, one of the ends being covered with a glass cover adapted to be pressed against the skin of a patient, the other end being adapted for viewing by an operator. A white light source (e.g., lamp) and illuminating optics are disposed within the housing for illuminating the skin sample, and magnifying optics are appropriately positioned within the housing for magnifying the illuminated skin sample for viewing by the operator.
Typically, in use, the operator applies mineral oil or organic chemical solvent (alcohol) the skin to be examined and then presses the glass cover of the dermatoscope against the solvent or oil-covered skin. The mineral oil or solvent substantially matches the index of refraction of the outermost layers of skin and, thereby, renders said outermost layers sufficiently translucent to permit observation of underlying skin structures. The magnifying optics of the dermatoscope permits observation of structures that would otherwise be too small to detect with the unaided eye or with a magnifying glass.
Although, as explained above, conventional dermatoscopes provide a measure of improvement over the unaided eye or a magnifying glass, conventional dermatoscopes still suffer from certain drawbacks. One such drawback is that the operator must bring his/her face down into proximity with the dermatoscope and, by extension, must bring his/her face down into proximity with the patient""s skin. As can readily be appreciated, such an arrangement is not hygienic. Another such drawback is that no permanent record of the observation of the skin is taken as the skin is viewed directly by the operator. Also, no telemedicine information can be relayed for expert diagnosis and advice.
Accordingly, one type of modification that has been made to conventional dermatoscopes has been to include means for producing and recording a videoimage of the examined skin. An example of such a dermatoscope is disclosed in U.S. Pat. No. 5,825,502, inventor Mayer, which issued Oct. 20, 1998, and which is incorporated herein by reference. According to the aforementioned patent, there is disclosed a mobile device for close-up-photography or videorecording that is easily usable for the investigation of surface details of an object which is particularly large and soft, for example, human skin. When placed in contact with the surface of the object, then without further adjustments a sharp and greatly enlarged image is obtained. The device includes a distance-enforcing structure between the optical system and the object which in the object-side focal area ends with a vaulted surface. The vaulted surface is mechanically stiff and is shaped to compensate the image-plane curvature of the optical system by establishing a corresponding object-plane curvature. This compensation: enhances the sharpness of the image obtained for an object surface which is pressed against the vaulted surface and thus is positioned in the true object-side focal area of the optical system.
Another example of a dermatoscope that includes means for producing and recording a videoimage of examined skin is disclosed in U.S. Pat. No. 6,010,450, inventor Perkins, which issued Jan. 4, 2000, and which is incorporated herein by reference.
Another problem associated with the examination of skin, whether said skin is observed with the unaided eye or with the aid of a derniatoscope, is that the analysis of the observed image often requires the application of qualitative and/or poorly-defined criteria. Such criteria may be judged differently by different individuals, thereby, leading to a lack of uniformity in diagnosis among various observers. Accordingly, one approach to this problem has been to automate the analysis of the recorded images obtained using a dermatoscope. An example of the aforementioned approach is described by Seidenari et al. in xe2x80x9cDigital videomicroscopy and image analysis with automatic classification for detection of thin melanomas,xe2x80x9d Melanoma Research, 9:163-171 (999), the disclosure of which is incorporated herein by reference.
As can readily be appreciated, one disadvantage associated with the use of dermatoscopes of the types described above is that mineral oil, solvent or the like must be applied to the patient""s skin in order to minimize diffuse reflection at the outermost layer of skin and, in so doing, to render the skin more transparent to white lamp light. One approach to this problem has been to have the dermatoscope use polarized lamp light to illuminate the skin under examination and to have the dermatoscope image the underlying structures of the illuminated skin using the perpendicular component of the reflected light. An example of this approach is disclosed in U.S. Pat. No. 6,032,071, inventor Binder, which issued Feb. 29, 2000, and which is incorporated herein by reference. According to the aforementioned patent, a device for optical examination of human skin and its pigmentation is described that comprises a cylindrical housing in which are arranged an optical observation device and a vertical illumination device. Where it faces the skin, the housing is delimited by a plate made of transparent plastics or glass, which is applied to a skin site to be examined without introducing an immersion fluid. Light polarization devices are situated between the illumination device and the transparent plate and between the transparent plate and the optical observation device, their degree of polarization being controlled or, optionally, their location being movable mechanically into or out of particular light beam paths.
Although dernatoscopes of the types described above have enabled significant advances in skin examination to take place, substantial room for improvement still exists.
Other patents and publications of interest include U.S. Pat. No. 5,719,399, inventors Alfano et al., issued Feb. 17, 1998; U.S: Pat. No. 5,847,394, inventors Alfano et al., issued Dec. 8, 1998; U.S. Pat. No. 5,929,443, inventors Alfano et al., issued Jul. 27, 1999; Gutkowicz-Krusin et al., Skin Research and Technology, 3:15-22 (1997); Robert Pini, Biophotonic International, pages 20-21 (September 1998); Kopf et al., Skin Research Technology, 3:1-7 (1997); Nachbar et al., J. Am. Acad. Dermatol., 30(4):551-9 (1994); and Menzies et al., xe2x80x9cA sensitivity and specificity analysis of the surface microscopy features of invasive melanoma,xe2x80x9d Melanoma Res., 6(1):55-62 (1996), all of which are incorporated herein by reference.
It is an object of the present invention to provide a new apparatus suitable for use in examining skin, mucosa and cervical tissues for the purpose of detecting cancer and precancerous conditions therein.
It is another object of the present invention to provide an apparatus as described above that overcomes at least some of the problems associated with existing devices for performing such examinations.
Therefore, according to one aspect of the invention, there is provided an apparatus suitable for use in examining skin, mucosa and cervical tissues for the purpose of detecting cancer and precancerous conditions therein, said apparatus comprising (a) first illuminating means for illuminating an object with polarized light of a first color; (b) second illuminating means for illuminating an object with polarized light of a second color, said second color being different from said first color; (c) a control coupled to each of said first illuminating means and said second illuminating means to permit selective actuation of said first illuminating means and said second illuminating means; (d) a light detector for outputting an electrical signal in response to light incident thereonto; (e) an adjustable polarizer positioned between said light detector and the illuminated object; (f) optics for imaging light emitted from the illuminated object onto said light detector; (g) a computer for processing the output from said light detector; (h) means for transmitting the output from said light detector to said computer; and (i) a display for displaying the results of said processing from said computer. The display may be located proximally relative to said computer and connected directly thereto or may be located remotely relative to said computer and connected to said computer, for example, via modem and a second computer.
In a preferred embodiment, the apparatus comprises a gun-shaped housing having a handle portion and a barrel portion. The front end of the barrel portion is open, and a glass cover is mounted therein. Red, green, blue, and white LED""s are disposed within the handle portion of the housing and are electrically connected to a battery also disposed within the handle portion of the housing. A manually-operable switch for controlling actuation of each of the four LED""s is accessible on the handle portion of the housing. An optical fiber is disposed inside the housing and is used to transmit light from the four LED""s, through a first polarizer disposed in the barrel portion of the housing and then through the glass cover to illuminate a desired object. Reflected light from the object entering the housing through the glass cover is passed through a second polarizer, which is adjustably mounted in the barrel portion of the housing, and is then imaged by optics onto a CCD detector. The optics may include a lens that is disposed within the barrel portion and is adjustably spaced relative to the CCD detector. The detector is coupled to a wireless transmitter mounted in the housing, the transmitter transmitting the output from the detector to a remotely located wireless receiver. The wireless receiver is coupled to a computer, which then processes the output from the detector. The processed output is then displayed on a display or relayed by telemedicine to remote sites for diagnosis by experts.
Additional objects, features, aspects and advantages of the present invention will be set forth, in part, in the description which follows and, in part, will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration specific embodiments for practicing the invention. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.